Pregnancy leads to a number of skin changes but empirical evidence about the structural and functional changes of the skin is scarce. Findings on skin structure and function in newborns and children in the first year of life reveal a rapid skin maturation after birth, but evidence indicates, that in particular water-holding and transport mechanisms are very different to adults in the first year in life. The most important open question is whether and how the maternal cutaneous properties predict the skin function of their children. This is especially relevant for the skin microbiome, because it closely interacts with the host and is assumed to play a role in many skin diseases. Therefore, the objective of this study is the description of characteristics of skin and hair structure and skin function of pregnant women and their newborns during pregnancy and for both in the first six months after delivery. In addition, we investigate associations of the mother's and their newborns skin microbiomes, and changes thereof in the newborns within the first six months of life.

The study has a descriptive, exploratory, longitudinal design. We will recruit pregnant females between 18 to 45 years old using advertisement campaigns, study information material in the waiting areas of their gynecologists, in pregnancy preparation services and in hospital's outpatient services. If they are interested and fulfill the inclusion criteria, they are invited to participate. Taking into account an assumed dropout rate of about 30%, a final sample of n = 100 women is expected. A detailed dermatological examination and general medical condition are documented. Non-invasive, standardized skin and hair physiological and skin microbiome measurements are performed during the visits. Baseline is scheduled during pregnancy until late 4 weeks before delivery. Follow-up visits are scheduled 4 weeks and 6 months after birth for mothers and newborns. Descriptive statistical methods will be calculated for frequencies and associations over time depending on scale levels of the measurements.

In our longitudinal study, we will characterize a broad range of individual and environmental characteristics of mothers and their newborns to evaluate interrelationships with skin parameters and their changes over the period of at least 8 months. Considering these multiple variables and levels together will allow a deeper understanding of the complex interrelationship of the newborns skin maturation.

A longitudinal descriptive, exploratory cohort study will be performed including females during pregnancy, puerperium and their newborns until sixth months of life.

Women will be invited after the first pregnancy trimester from the federal state of Berlin (Germany) during their visits to gynecologists and/or midwives. Inclusion and all study visits and measurement procedures will be conducted at the Clinical Research Center for Hair and Skin Science at the Department of Dermatology at the Charité-Universitätsmedizin Berlin (Germany). If meeting the eligibility criteria women will be included into the study. After inclusion into the study during the baseline visit, women will be followed at date of delivery + four weeks and followed further at the sixth month after delivery. The newborn/infants will be examined up to four weeks after birth and will be followed at sixth month after birth.

Due to the descriptive and exploratory nature of this study a broad range of characteristics and variables will be measured. Main aspects are skin structure, skin function and skin microbiome in one skin area. Skin structure will be measured by means of skin surface topography, epidermal thickness, skin stiffness and elasticity. Skin function will be measured by means of stratum corneum hydratation (SCH), TEWL and skin surface pH, which are established parameters to characterize the skin barrier function. Skin microbiome is defined as bacterial diversity, in detail the relative abundance of phylotypes, operational taxonomic units (OTU) will be measured. Hair growth will be measured on central and occipital scalp by means of hair density, hair widths.

Inclusion criteria

• written informed consent
• clinically healthy skin and hair appearance
• being free of any dermatological condition
• acceptance to abstain from sunbathing
• acceptance to abstain from solarium
• agreement to use the same skin cleaning and caring procedures during the study

Exclusion Criteria:

• regular smoking
• regular alcohol intake
• any dermatological condition or skin affection which may interfere with the study assessments (psoriasis, atopic dermatitis or other lesions at the investigational sites)
• clinically significant, possibly unstable medical conditions due to gravidity such as gestosis, eclampsia or thrombosis.
• Criteria related to treatments and products such as current topical or systemic treatment possibly affecting the skin, (diuretics, cholesterol-lowering drugs, hormones) during past four weeks
• therapeutic ultraviolet radiation within six weeks before inclusion
• increased ultraviolet-exposure within six weeks before inclusion

Pregnant women and their newborns